SARS rivals TB for permanent lung damage

About 10 per cent of SARS survivors appear to be left with lung damage that renders them unable to perform routine tasks without struggling for breath, according to doctors.

Although most patients stricken by severe acute respiratory syndrome are believed to recover fully, this marks the first time researchers have found that some who survive may have to contend with permanent breathing problems.

The Hong Kong doctors' revelation adds to the growing recognition that SARS is among the most dangerous lung infections, rivalling a scourge such as tuberculosis. The report comes just days after the World Health Organisation doubled its estimate of the death rate from SARS to about 15 per cent overall, far higher than the mortality rates of most other respiratory illnesses.

China remains the hardest hit by SARS with 235 deaths. Thousands more are being kept in quarantine amid fears that the disease is spreading from cities - particularly badly affected Beijing - and into the impoverished countryside where medical facilities would not be able to cope with a sweeping epidemic. And in Taiwan, the subway system in the capital, Taipei, has became a new front in the war against the virus as officials fear the illness is spreading from the capital and through the south of the island.

Taiwan, hoping to curb the outbreak, is installing video cameras to watch about 8000 people quarantined in their homes in case they have contracted the virus.

Because SARS is so new, some of the most basic information about it - such as how to treat it, how long people are sick, how many recover and whether it can cause long-term health problems - has been unknown. But the first answers have begun to become clear in recent weeks as doctors have gained experience with the illness.

In Hong Kong at the weekend, doctors and public health officials provided the most detailed description yet of the new lung infection's typical course.

Hong Kong authorities said SARS had three distinct phases, each lasting about a week - the "viral replicative phase", the "immune hyperactive phase" and the life-threatening "pulmonary destruction phase".

About 80 per cent of patients recover after the second phase, but the remaining 20 per cent go on to the third stage and experience intense lung tissue damage. Most require intensive care, a respirator and oxygen to help them breathe.

"The numbers are pretty nasty," WHO spokesman Ian Simpson said. "It's less infectious than a disease like influenza but has a more serious impact on those who do get infected."

"If (SARS victims) want to exercise they will tend to get shortness of breath."

Doctors have now determined that about 10 per cent of infected patients seem to suffer continued breathing problems.

"We will notice that some of these patients will still have cough, and if they want to exercise they will tend to get shortness of breath more easily," Hong Kong's Secretary for Health, Welfare and Food, Dr Yeoh Eng-kiong, said. "This will certainly affect their ability to do exercise, and if they want to return to work sometimes they might find it hard to do so."

As a result, doctors have started a respiratory rehabilitation program to help survivors' lungs recover. It remains unclear, however, whether the damage will ever fully heal even with rehabilitative therapy, and whether that 10 per cent figure for long-term damage will change as doctors get more experience.